Anyone, albeit a skilled tradesman, an avid handyman, or a novice weekend tool man, when trying to tighten a small bit or tool into a drill chuck must hold the bit or tool with one hand while tightening the chuck. With larger diameter bits or tools, it is easier to place the tool into the chuck and tighten it since the jaws contact the tool or bit balancing it in the chuck. However, when tightening tools that have a diameter less than a quarter inch, often times the tool gets caught between adjacent jaws during tightening. Thus, the chuck must be reversed, the tool removed from between adjacent jaws and then centered in the chuck and further tightened. Two methods to deal with this problem are: (1) holding the tool with one hand while tightening the jaws to clamp around the tool; or (2) attempting to close the jaws to an approximate size so that the tool will not be caught between the jaws and further tightening the chuck. Thus, it is desirable to have a centering device which enables the tradesman to tighten the chuck without holding the tool in place.
The present invention provides the art with a chuck which includes a device to center tool bits within the chuck and enable tightening of the chuck around the tool. The present invention provides a mechanism between adjacent jaws which exerts a force to center tool bits within the chuck. The present invention is resilient enough to deflect, when larger diameter tools are inserted into the chuck, and rigid enough so that, when smaller diameter tools are inserted into the chuck, it centers the tool within the chuck. Also, the invention includes jaws that have tool contacting surfaces which are angled at about 135° with respect to one another. This enables adjacent jaws to guide small diameter tools from the periphery of the chuck bore towards the center of the bore to converge the tools between the jaws.
In accordance with the present invention, a chuck for a drill comprises a body member having a wall defining a bore to receive a tool to be retained within the chuck. Jaw members are received in the body member. The jaw members frictionally engage the tool to retain it in the chuck. A mechanism to open and close the jaw members is associated with the jaw members and the body to move the jaw members between a clamping and a non-clamping position. A centering mechanism extends radially into the body member bore. The centering mechanism prohibits tools from contacting the body member wall and enables the jaw members to contact and clamp the tool. The centering mechanism is positioned between adjacent jaw members. The centering mechanism includes a plurality of projecting members, each projecting member is positioned between an adjacent jaw member. The centering mechanism is manufactured from a resilient material that enables the mechanism to bend into the bore and to return to its original position. The projecting members generally include a neck secured to the body member near the wall and a head adjacent the jaw members. Also, the projecting member could include an adhesive strip secured to the wall with a plurality of hook or loop type members on each strip. Each jaw has a pair of tool contacting faces. The faces abut one another and form at an obtuse angle with a measurement of about 135°. A spacer may be positioned in the bore. The spacer may have at least one rib to center the tool when the tool contacts the spacer.
According to a second aspect of the invention, a power tool comprises a housing with a motor inside the housing. An output is coupled with the motor. The power tool includes a power source and an actuation member coupled with the power source and the motor to activate the motor to drive the output. A chuck is coupled with the output. The chuck comprises a body member having a wall defining a bore to receive a tool to be retained within the chuck. Jaw members are received in the body member. The jaw members frictionally engage the tool to retain it in the chuck. A mechanism to open and close the jaw members is associated with the jaw members and the body to move the jaw members between a clamping and a non-clamping position. A centering mechanism extends radially into the body member bore. The centering mechanism prohibits tools from contacting the body member wall and enables the jaw members to contact and clamp the tool. The centering mechanism is positioned between adjacent jaw members. The centering mechanism includes a plurality of projecting members, each projecting member is positioned between an adjacent jaw member. The centering mechanism is manufactured from a resilient material enabling the mechanism to bend into the bore and to return to its original position. The projecting members generally include a neck secured to the body member near the wall and a head adjacent the jaw members. Alternatively, the projecting member could include an adhesive strip secured to the wall with a plurality of hook or loop type members on each strip. Each jaw has a pair of tool contacting faces. The faces abut one another to form at an obtuse angle with a measurement of about 135°. A spacer may be positioned in the bore. The spacer may have at least one rib to center the tool when the tool contacts the spacer.
According to a third aspect of the invention, a chuck comprises a body member having a wall which defines a bore to receive a tool to be retained within the chuck. Jaw members are received in the body member. The jaw members frictionally engage the tool to retain the tool within the chuck. A mechanism to open and close the jaw members is associated with the jaw member and the body member to move the jaw members between a clamping and a non-clamping position. The chuck includes a plurality of centering members. Each centering member is positioned between an adjacent jaw members creating a jaw member, centering member, repeating pattern. Each centering member is made of a material rigid enough to support small tools from deflecting the centering member so that the centering members enable the jaw members to clamp the small tools without the small tools becoming wedged between adjacent jaw members. Also, the centering members are resilient enough to easily deflect when large tools are positioned in the bore which have a diameter larger than the diameter defined between the ends of the plurality of the centering members. The plurality of centering members each have a neck and a head such that the heads extend towards one another. The plurality of centering members are manufactured from Mylar, Nitinol, spring steel or the like.
From the following detailed description taken in conjunction with the drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.